Problem: $(18+4i)+(-11+23i)=$ Express your answer in the form $(a+bi)$.
Answer: Background Complex numbers can be added or subtracted by separately adding or subtracting their real and imaginary terms. To add or subtract complex numbers: Expand parentheses (attending to minus signs outside of parentheses if necessary) Combine all real terms (terms that do not contain $i$ ), and add or subtract them. Combine all imaginary terms (terms that contain $i$ ), and add or subtract them. Combining Like Terms $\begin{aligned} ({18}+{4}i)+({-11}+{23}i)&={18}+{4}i{-11}+{23}i \\\\ &={18}{-11}+{4}i+{23}i \\\\ &={7}+{27}i \end{aligned}$ Summary $({18}+{4}i)+({-11}+{23}i)={7}+{27}i$